The present invention relates to an apparatus and process for filtering water in general, and to an apparatus and process for removing contaminants such as iron, manganese and sulfur, from water, such as well water.
Many households and commercial facilities use well water as their source of water, either drinking water, cooling water, make-up water, or for other residential or industrial uses. Well water commonly contains naturally occurring mineral contaminants, such as iron, sulfur, copper, and manganese. These contaminants affect the odors and taste of the water, and may also stain plumbing fixtures and corrode pipes.
Mineral contaminants are commonly removed from water by entraining air (which includes oxygen) in the raw water and passing the aerated water through a bed of particulate such as calcium carbonate or dolomite to raise the pH level of the water and facilitate precipitation of the undesirable minerals. The dissolved oxygen in the water, in particular, enhances the oxidation of soluble iron II to insoluble iron III. Air is often added to the raw water, usually during a back wash cycle, by passing the water through a pipe section of decreasing cross-sectional area with an air inlet known as a venturi nozzle. The increased pH water may then be passed through one or more filter media to remove the precipitated contaminants.
What is desired is an improved water filtration system, one which supplies the oxygen for the necessary aeration of the raw water to produce satisfactory oxidation of the unwanted minerals without reducing available water pressure and which is not susceptible to clogging or degradation due to water flow.
U.S. Pat. No. 5,096,596 to Hellenbrand et al. provides one design. This patent describes an apparatus for removing mineral contaminants from water which has an aeration tank connected to a supply of water, an inlet for admitting the water to the aeration tank and an outlet for discharging water. A diffuser is connected to the aeration tank inlet and has a plurality of apertures which permit the diffusion of the contaminated water into an airhead within the aeration tank. A controller controls a source of compressed air to permit oxygen to be supplied independently of the water supply to the interior of the aeration tank for recharging the aeration tank with oxygen. A bed of calcium carbonate chips may be positioned inside the aeration tank beneath the spray of contaminated water. A pick-up tube has an open end located above the bed of calcium carbonate chips and is connected to the outlet of the aeration tank. A filter tank has an inlet connected to the pick-up tube of the aeration tank and an outlet adapted to be connected to a water supply line. The system has a distributor tube connected to the outlet of the filter tank with an opening within the multimedia filter bed, so that the oxygenated water may be drawn through the multimedia filter bed so that a significant portion of the contaminants may be removed from the water and the filtered water may be supplied to the outlet of the filter tank. The system has a multimedia filter bed positioned within the filter tank which has a plurality of filtration layers.
There is always room for alternate designs.